This invention relates generally to an electro-optical device and more particularly to an electro-optical device in which a liquid crystal is sandwiched between flexible substrates including gas barrier layers and separated by spacers.
A prior art electro-optical device including a flexible substrate is described in Japanese Patent Laid-Open Application No. 60-6982. Polyvinylidene chloride which acts a gas barrier layer is laminated on a phenoxy resin substrate at the surface opposite to the liquid crystal layer to form a flexible substrate. The gas barrier layer improves the display, however, the device is not fully adequate. As a result, gas enters the liquid crystal material through the substrate and bubbles cause defects in the display. Additionally, part of the polyvinylidene chloride resin dissolves and chlorine gas is discharged. This results in an increase in the current value of the liquid crystal display device and lower reliability. Additionally, the resin becomes discolored leading to a poor quality display.
Japanese Patent Laid-Open Application No. 60-153025 shows a prior art electro-optical device having spacers fixed to the aligning or orientation film on a flexible substrate. The aligning treated film is provided in the region where the upper and lower substrate are sealed together. Since the adhesion between the substrate film and the orientation film is weak, a poor bond between the opposed substrates occurs which can cause the substrate to puncture due to pressure. Additionally, when the aligning treated film is not formed in the region where the sealing compound is placed, there are no spacers so that the upper substrate contacts the lower substrate in that region. This results in incomplete sealing and wide variation in cell thickness. It has been suggested to eliminate the space between the aligning film and the sealing compound, however, this is not practical in terms of positional accuracy.
Furthermore, depending upon the hardness of the aligning film on which the spacers are fixed, there is a wide variation in the amount the spacers sink into the substrate surface. Thus, cell thickness is not fully uniform.
Accordingly, it is desireable to provide an electro-optical device which does not permit gas bubbles to permeate the liquid crystal layer through the flexible substrate, which does not suffer from irregular color caused by variation in thickness when the substrate is bent or twisted.